1. Field of the Invention
The present invention relates to a stress transmission device which is provided between a pile head of a foundation pile and an upper construction portion for transmitting stress between the upper construction portion and the foundation pile, and to a structural element using the same and to a method of construction thereof.
The present application is based upon Japanese Patent Applications Serial Nos. 2000-108477, 2000-169841, 2000-254521, 2000-261948, and 2000-267764, and the contents of said applications are hereby incorporated into the present application by reference.
2. Description of the Related Art
In the prior art, when constructing a building, it is generally performed to support an upper structural portion upon a pile which is emplaced in a supporting ground slab, and moreover to support the entire upper structural portion in this manner.
Although in the prior art the pile head has been rigidly linked to the upper structural portion, in this case if, during an earthquake, a horizontal force is received upon the pile head, there is a fear that the pile head will be destroyed, and in order to prevent this it has become necessary to strengthen the pile head portion by increasing its diameter or the like.
In this connection, in order to reduce the stress which acts upon the pile head, a pin connecting construction has been proposed which connects the pile head to the upper structural portion in a manner to allow relative rotation therebetween, thus being made so as to release the stress upon the pile head; and also a roller connection construction has been proposed which allows sliding movement of the pile head with respect to the building, thus releasing the stress upon the pile head (for example, see Japanese Patent Application Laying-Open Publications Serial Nos. Heisei 1-284613, Heisei 8-120687, Heisei 10-227039, and 10-227040).
However, with a construction such as described above, so as to generate the desirable relative displacement between the pile head and the upper structural portion, it is necessary to reduce the amount of friction between the pile head and the upper structural portion. For this, in order to make the contacting surfaces between the pile head and the upper structural portion smooth, it is necessary to employ a resin process or a mechanical process or the like, and this entails an increase in cost.
Furthermore, with a construction such as described above, when attempting to permit relative displacement between the pile head and the upper structural portion, according to circumstances, there may be a danger of not being able reliably to perform transmission of shearing force.
Moreover, with a construction such as described above, although force may well act in the direction to separate the pile head and the upper structural portion, in the prior art, while allowing relative displacement between the pile head and the upper structural portion, it has not been considered to prevent these from coming apart in the upward direction.
Yet further, since with a construction such as described above the frictional force between the mutually superimposed surfaces has an important effect, it has been necessary to ensure that this frictional force between these surfaces should not vary due to concrete which is poured during constructing flowing in between these surfaces, or due to the generation of corrosion because of invasion of ground water after construction, or due to the invasion of earth or sand or the like.
Still yet further, in order to provide a construction such as described above, after the pile head has been formed, it has been necessary to wait for the concrete which has been poured for the pile head to harden, and to perform processing upon the pile head, and thereafter the process of providing the above described construction has been necessary, which has all necessitated using a time period greater than prescribed.
The present invention has been conceived as a result of consideration of this type of problem, and has as its objective to propose a stress transmission device, and a structure which employs it, which, without any accompanying elevation of cost, while preventing the transmission of bending moment between the pile head and the upper structural portion, also in this case can satisfactorily cope with shearing force or pulling force or the like acting between the pile head and the upper structural portion.
Further, another objective of the present invention is to propose a stress transmission device, and a structure which employs it, which reliably prevent the entry of foreign objects or matter between the contacting surfaces, so as reliably to realize their function.
Further, another objective of the present invention is to propose a structure and a method of constructing the same, in which the above described stress transmission device can reliably be set up in a short time period, and which thereby make it possible to shorten the period of construction.
In order to attain the above described objectives, the present invention utilizes the following means.
A first aspect of the present invention is a stress transmission device, comprising a pile head member which is set upon a pile head of a foundation pile, and a structure support member which is fixed to an upper structural portion and is arranged to face said pile head member, and said pile head member and said structure support member mutually contact one another in the vertical direction via a first contacting surface which defines a portion of a first imaginary spherical surface, and a tension member is fitted to said pile head member and said structure support member for holding them together in contact while pressing them together via said first contacting surface.
According to the above described structure, it is possible to prevent the structure support member from rising up from the pile head member, provided that the pulling force which acts between the pile head member and the structure support member is less than the pushing force of the tension member.
According to another aspect of the present invention, one of said pile head member and said structure support member is provided with a spherical seat and a concave surface is formed upon the other, and said first contacting surface is constituted by mutually contacting together the outer surface of said spherical seat and said concave surface, and the outer surface of said spherical seat is formed so as to define the same surface as said first imaginary spherical surface, and a through hole is formed in said concave surface for passing through said tension member, and an aperture portion is formed in a position of said spherical seat which opposes said through hole, and, along with said tension member being arranged so as to pass through said through hole and said aperture portion, both its ends are respectively engaged to said pile head member and said structure support member by engagement members.
According to the above described structure, it is possible to press the pile head member and the structure support member together via the first contacting surface.
According to another aspect of the present invention, said tension member is arranged so that its central axis lies along the vertical axis which passes through the center of curvature of said spherical seat.
According to the above described structure, it is ensured that the component of the pushing force between the spherical seat and the concave surface which is perpendicular to the first contacting surface does not become excessive in the vicinity of the outer edge portion of the spherical seat.
According to another aspect of the present invention, one of said engagement members which are provided at both the ends of said tension member contacts said pile head member or said structure support member via a second contacting surface which defines a portion of a second imaginary spherical surface, and the centers of curvature of said first and said second imaginary spherical surfaces coincide.
According to the above described structure, when the pile head member and the structure support member undergo mutual relative displacement along the first imaginary spherical surface, it is possible for the tension member to be displaced relative to the pile head member and the structure support member in the same direction.
According to another aspect of the present invention, the diameter of a one of said through hole and said aperture portion at said first contact surface is greater than that of the other; and the radial dimensions of said through hole and said aperture portion are determined so that, when said pile head member and said structure support member are relatively displaced through the maximum rotational angle which is anticipated to take place between said foundation pile and said upper structural portion, at said first contacting surface, said other of said through hole and said aperture portion is positioned in the interior of said one.
According to the above described structure, no change of the surface area of the first contacting surface takes place, even when the through hole and the aperture portion undergo mutual relative displacement.
According to another aspect of the present invention, the radial dimensions of said through hole and said aperture portion are determined so that their inner circumferential surfaces are positioned outside the range in which said tension member is positioned, when said pile head member and said structure support member are relatively displaced through the maximum rotational angle which is anticipated to take place between said foundation pile and said upper structural portion.
According to the above described structure, it is ensured that no contact occurs between the tension member and the inside circumferential surfaces of the through hole and of the aperture portion.
Another aspect of the present invention is a structure, comprising a foundation pile, an upper structural portion which is supported by said foundation pile, and, between said foundation pile and said upper structural portion, a stress transmission device for transmitting stress therebetween, comprising a pile head member which is set upon a pile head of said foundation pile, and a structure support member which is fixed to said upper structural portion and is arranged to face said pile head member; wherein said pile head member and said structure support member mutually contact one another in the vertical direction via a first contacting surface which defines a portion of a first imaginary spherical surface; and a tension member is fitted to said pile head member and said structure support member for holding them together in contact while pressing them together via said first contacting surface.
According to another aspect of the present invention, one of said pile head member and said structure support member is provided with a spherical seat and a concave surface is formed upon the other, and said first contacting surface is constituted by mutually contacting together the outer surface of said spherical seat and said concave surface; the outer surface of said spherical seat is formed so as to define the same surface as said first imaginary spherical surface; a through hole is formed in said concave surface for passing through said tension member, and an aperture portion is formed in a position of said spherical seat which opposes said through hole; and along with said tension member being arranged so as to pass through said through hole and said aperture portion, both its ends are respectively engaged to said pile head member and said structure support member by engagement members.
According to another aspect of the present invention, said tension member is arranged so that its central axis lies along the vertical axis which passes through the center of curvature of said spherical seat.
According to another aspect of the present invention, one of said engagement members which are provided at both the ends of said tension member contacts said pile head member or said structure support member via a second contacting surface which defines a portion of a second imaginary spherical surface, and the centers of curvature of said first and said second imaginary spherical surfaces coincide.
According to another aspect of the present invention, the diameter of a one of said through hole and said aperture portion at said first contact surface is greater than that of the other; and the radial dimensions of said through hole and said aperture portion are determined so that, when said pile head member and said structure support member are relatively displaced through the maximum rotational angle which is anticipated to take place between said foundation pile and said upper structural portion, at said first contacting surface, said other of said through hole and said aperture portion is positioned in the interior of said one.
According to another aspect of the present invention, the radial dimensions of said through hole and said aperture portion are determined so that their inner circumferential surfaces are positioned outside the range in which said tension member is positioned, when said pile head member and said structure support member are relatively displaced through the maximum rotational angle which is anticipated to take place between said foundation pile and said upper structural portion.
Another aspect of the present invention is a stress transmission device, comprising a pile head member which is set upon a pile head of a foundation pile, and a structure support member which is fixed to an upper structural portion which is supported by said foundation pile, and is arranged to face said pile head member; wherein: said pile head member and said structure support member mutually contact one another in the vertical direction via a contacting surface which defines a portion of an imaginary spherical surface; and said contacting surface is formed in an annular shape whose central axis is the vertical axis through the center of curvature of said imaginary spherical surface.
If the above described structure is employed, it is possible to reduce the component in the normal direction of the contacting surface of the axial force which acts upon the pile head member from the structure support member, as compared to the case in which they contact over a predetermined range in the vicinity of the vertical axis of the imaginary spherical surface as a contacting surface between the pile head member and the structure support member. Further, it is likewise possible to reduce the component which tends to generate horizontal slippage of the horizontal force which acts between the pile head member and the structure support member.
According to another aspect of the present invention, said contacting surface is constituted as the contact surface between a convex surface which is formed upon one of said pile head member and said structure support member and a concave surface which is formed upon the other; and at least a one of said convex surface and said concave surface is formed from an outer ring portion and a central portion whose central axis is said vertical axis, and said outer ring portion constitutes a surface the same as said imaginary spherical surface, while said central portion is shaped as concave, taking said imaginary spherical surface as a reference.
According to the above described structure, the central portion of one of the convex surface and the concave surface does not contact the other, and only its outer ring portion comes to be in contact with the other.
According to another aspect of the present invention, said central portion is formed as an aperture portion in said convex surface or in said concave surface.
By this type of structure, the central portion can easily be formed in a concave shape.
According to another aspect of the present invention, said central portion is a horizontal surface which is formed upon said convex surface.
According to this type of structure, it is possible to form the central portion in a concave shape, taking the imaginary spherical surface as a reference, by a simple process.
According to another aspect of the present invention, the outer circumferential edge portion of said convex surface is formed as a curved surface whose radius of curvature in a vertical cross section is smaller than that of said imaginary spherical surface.
According to this type of structure, it is possible to reduce the friction at the outer circumferential portion of the concave surface, and this portion is prevented from becoming a support point when relative rotational displacement takes place between said convex surface and said concave surface.
Another aspect of the present invention is a structure, comprising a foundation pile, an upper structural portion which is supported by said foundation pile, and, between said foundation pile and said upper structural portion, a stress transmission device for transmitting stress therebetween, comprising a pile head member which is set upon a pile head of said foundation pile, and a structure support member which is fixed to said upper structural portion and is arranged to face said pile head member; wherein said pile head member and said structure support member mutually contact one another in the vertical direction via a contacting surface which defines a portion of an imaginary spherical surface; and said contacting surface is formed in an annular shape whose central axis is the vertical axis through the center of curvature of said imaginary spherical surface.
According to another aspect of the present invention, said contacting surface is constituted as the contact surface between a convex surface which is formed upon one of said pile head member and said structure support member and a concave surface which is formed upon the other; and at least a one of said convex surface and said concave surface is formed from an outer ring portion and a central portion whose central axis is said vertical axis, and said outer ring portion constitutes a surface the same as said imaginary spherical surface, while said central portion is shaped as concave, taking said imaginary spherical surface as a reference.
According to another aspect of the present invention, said central portion is formed as an aperture portion in said convex surface or in said concave surface.
According to another aspect of the present invention, said central portion is a horizontal surface which is formed upon said convex surface.
According to another aspect of the present invention, the outer circumferential edge portion of said convex surface is formed as a curved surface whose radius of curvature in a vertical cross section is smaller than that of said imaginary spherical surface.
Another aspect of the present invention is a stress transmission device, comprising a pile head member which is set upon a pile head of a foundation pile, a structure support member which is fixed to an upper structural portion and is arranged to face said pile head member, and a pulling out resistant member which is fixed with respect to one or the other of said foundation pile and said upper structural portion and is arranged so as to project towards the other; wherein said pile head member and said structure support member mutually contact one another in the vertical direction via a first contacting surface which defines a portion of a first imaginary spherical surface; said pulling out resistant member is made so as to be stopped with respect to at least one of said pile head member and said structure support member, when said upper structural portion is displaced in the direction to separate it from said foundation pile; said pulling out resistant member, when it is stopped with respect to said pile head member or said structure support member, contacts said pile head member or said structure support member via a second contacting surface which defines a portion of a second imaginary spherical surface, and the centers of curvature of said first and said second imaginary spherical surfaces coincide.
If this type of structure is utilized, it is possible satisfactorily to rotationally displace the upper structural portion with respect to the foundation pile, since relative displacement between the pile head member and the structure support member can take place along the first imaginary spherical surface. Further, it is possible to stop the upper structural portion from coming up away from the foundation pile, due to the provision of the pulling out resistant member. Yet further, in this case, since the pulling out resistant member can be relatively displaced with respect to one or the other of the pile head member and the structure support member along the second imaginary spherical surface, therefore the pulling out resistant member offers no impediment to the mutual rotational displacement of the upper structural portion and the foundation pile.
According to another aspect of the present invention, said first contacting surface is formed in an annular shape whose central axis is the vertical axis through the center of curvature of said first imaginary spherical surface.
According to this type of structure, by comparison to the case in which the pile head member and the structure support member contact one another over a predetermined range in the vicinity of the vertical axis of the first imaginary spherical surface as the first contacting surface, it is possible to reduce the component in the normal direction of the contacting surface of the axial force which acts upon the pile head member from the structure support member, and by doing this it is likewise possible to reduce the frictional resistance at the first contacting surface. Further, it is also possible to reduce the component which tends to generate horizontal slippage of the horizontal force which acts between the pile head member and the structure support member.
According to another aspect of the present invention, a spherical seat whose interior is empty is provided to said pile head member and a concave surface is formed upon said structure support member, and said first contacting surface is defined by the mutual contact of an outer surface of said spherical seat and said concave surface; along with the outer surface of said spherical seat being formed so as to define a surface which is the same as said first imaginary spherical surface, its inner surface is formed so as to define a surface which is the same as said second imaginary spherical surface, and moreover said spherical seat comprises an aperture portion which is pierced through its said outer surface and its said inner surface; said pulling out resistant member comprises a rod shaped main portion which is fixet to said upper structural portion and a head portion provided at an end of said main portion whose radial dimension is greater than that of said aperture portion, and said main portion is passed through said aperture portion, while said head portion is arranged so as to be in a state confronting said inner surface of said spherical seat; and said second contacting surface is defined by the mutual contact between said head portion and said inner surface of said spherical seat.
According to this kind of structure, it is possible for the structure support member and the pulling out resistant member to contact the pile head member upon imaginary spherical surfaces which have the same center of curvature.
According to another aspect of the present invention, the central portion of said concave surface is shaped as concave, taking said first contacting surface as a reference.
According to this type of structure, the central portion of the concave surface does not contact the spherical seat, and only the outer edge portion on the outside of said central portion contacts said spherical seat.
According to another aspect of the present invention, a through hole is formed in the central portion of said concave surface for passing through said pulling out resistant member, and said aperture portion is formed in a position to face said through hole.
According to this type of structure, the pulling out resistant member is passed through the through hole in its state in which it is directly fixed to the upper structural portion, and, along with projecting towards the foundation pile from the central portion of the concave surface, its head portion can be put into the interior portion of the spherical seat.
According to another aspect of the present invention, the magnitude of the radial dimension of said aperture portion is determined so that said main portion of said pulling out resistant member and the inner surface of said aperture portion do not contact one another, when said pulling out resistant member is displaced through the maximum rotational angle which is anticipated to take place between said foundation pile and said upper structural portion.
According to such a structure, no impediment is offered to relative displacement between the pile head member and the structure support member by contact of the pulling out resistant member against the inner surface of the aperture portion.
According to another aspect of the present invention, concavities and convexities are provided upon said main portion of said pulling out resistant member for ensuring force for fixing said pulling out resistant member into concrete from which said upper structural portion is made.
According to this structure, it is possible to fix the pulling out resistant member very strongly to the upper structural portion.
According to another aspect of the present invention, upon said main portion of said pulling out resistant member, at a portion which is fixed to said upper structural portion, a radially enlarged portion is formed whose radial dimension is greater as compared to other portions of said main portion.
According to such a structure, it is possible to fix the pulling out resistant member very strongly to the upper structural portion.
According to another aspect of the present invention, said pulling out resistant member is made so that its said head portion and its said main portion can be separated from one another.
According to such a structure, it is possible to utilize different materials for the head portion and for the main portion of the pulling out resistant member.
Another aspect of the present invention is a structure, comprising a foundation pile, an upper structural portion which is supported by said foundation pile, and, between said foundation pile and said upper structural portion, a stress transmission device for transmitting stress therebetween, comprising a pile head member which is set upon a pile head of a foundation pile, a structure support member which is fixed to said upper structural portion and is arranged to face said pile head member, and a pulling out resistant member which is fixed with respect to one or the other of said foundation pile and said upper structural portion and is arranged so as to project towards the other; wherein said pile head member and said structure support member mutually contact one another in the vertical direction via a first contacting surface which defines a portion of a first imaginary spherical surface; said pulling out resistant member is made so as to be stopped with respect to at least one of said pile head member and said structure support member, when said upper structural portion is displaced in the direction to separate it from said foundation pile; said pulling out resistant member, when it is stopped with respect to said pile head member or said structure support member, contacts said pile head member or said structure support member via a second contacting surface which defines a portion of a second imaginary spherical surface, and the centers of curvature of said first and said second imaginary spherical surfaces coincide.
According to another aspect of the present invention, said first contacting surface is formed in an annular shape whose central axis is the vertical axis which passes through the center of curvature of said first imaginary spherical surface.
According to another aspect of the present invention, a spherical seat whose interior is empty is provided to said pile head member and a concave surface is formed upon said structure support member, and said first contacting surface is defined by the mutual contact of an outer surface of said spherical seat and said concave surface; along with the outer surface of said spherical seat being formed so as to define a surface which is the same as said first imaginary spherical surface, its inner surface is formed so as to define a surface which is the same as said second imaginary spherical surface, and moreover said spherical seat comprises an aperture portion which is pierced through its said outer surface and its said inner surface; said pulling out resistant member comprises a rod shaped main portion which is fixed to said upper structural portion and a head portion provided at an end of said main portion whose radial dimension is greater than that of said aperture portion, and said main portion is passed through said aperture portion, while said head portion is arranged so as to be in a state confronting said inner surface of said spherical seat; and said second contacting surface is defined by the mutual contact between said head portion and said inner surface of said spherical seat.
According to another aspect of the present invention, said pulling out resistant member is arranged so that its head portion is separated from the inner surface of said spherical seat, when the axial force which acts upon said stress transmission device is a compression force.
According to such a construction, if a pulling upward force does not act upon the upper structural portion, no frictional force is generated between the pulling out resistant member and the spherical seat.
According to another aspect of the present invention, the central portion of said concave surface is shaped as concave, taking said first contacting surface as a reference.
According to another aspect of the present invention, a through hole is formed in the central portion of said concave surface for passing through said pulling out resistant member, and said aperture portion is formed in a position to face said through hole.
According to another aspect of the present invention, the magnitude of the radial dimension of said aperture portion is determined so that said main portion of said pulling out resistant member and the inner surface of said aperture portion do not contact one another, when said pulling out resistant member is displaced through the maximum rotational angle which is anticipated to take place between said foundation pile and said upper structural portion.
According to another aspect of the present invention, concavities and convexities are provided upon said main portion of said pulling out resistant member for ensuring force for fixing said pulling out resistant member into concrete from which said upper structural portion is made.
According to another aspect of the present invention, upon said main portion of said pulling out resistant member, at a portion which is fixed to said upper structural portion, a radially enlarged portion is formed whose radial dimension is greater as compared to other portions of said main portion.
According to another aspect of the present invention, said pulling out resistant member is made so that its said head portion and its said main portion can be separated from one another.
Another aspect of the present invention is a stress transmission device, comprising, upon a pile head member which is provided to a pile head of a foundation pile, a structure support member, which is fixed to an upper structural portion and is superimposed upon a spherical surface of said pile head member, and which has a spherical surface which conforms to said spherical surface of said pile head member; and, between said superimposed spherical surfaces, a seal which seals said spherical surfaces from the outside is inserted.
Thus, according to this aspect of the present invention, the superimposed and contacting spherical surfaces are protected from the outside by the seal, and the invasion of concrete which is being poured, or of ground water, earth, or sand, is prevented.
According to another aspect of the present invention, a seal is provided between the outer surfaces of said superimposed pile head member and structure support member.
Accordingly the spherical surfaces are protected by this seal member at the outer circumferential edges of the pile head member and the structure support member, so that, in particular during transportation or during construction or the like, the invasion of foreign matter between the contacting spherical surfaces is effectively prevented.
Another aspect of the present invention is a structure, comprising a foundation pile, an upper structural portion which is supported by said foundation pile, and, between said foundation pile and said upper structural portion, a stress transmission device for transmitting stress therebetween, wherein said foundation pile is a cast-in-place concrete pile, and in the interior of an iron bar cage which is comprised in said foundation pile, an iron bar cage for anchoring of tubular shape whose diameter is smaller than that of said iron bar cage is disposed in the state of being embedded in the concrete from which said foundation pile is made; and said iron bar cage for anchoring comprises a plurality of anchoring reinforcement members which are arranged vertically, with the upper end portions of these anchoring reinforcement members being arranged in a state so as to project upwards higher than said pile head, and moreover a lower portion of said stress transmission device is fixed to said upper end portions, and also said iron bar cage for anchoring is connected to said iron bar cage via a position maintenance member.
According to this type of structure, when making the pile, it is possible to embed the iron bar cage for anchoring in the pile at the same time as pouring the concrete, and thereby it is possible to perform the pouring of the concrete for the pile and the emplacement of the anchoring arrangements at the same time.
According to another aspect of the present invention, said iron bar cage for anchoring is formed by mutually connecting together said anchoring reinforcement members by annular shaped ring members which are disposed to extend in the circumferential direction of said iron bar cage for anchoring, and a plurality of said position maintenance members of the same shape are provided between said iron bar cage and said ring members, and these position maintenance members are disposed so as to extend from the outer peripheral surfaces of said ring members in the radially outward directions of said ring members.
According to this type of structure, it is possible to ensure that the iron bar cage for anchoring is centralized in the iron bar cage by using these position maintenance members.
According to another aspect of the present invention, anchoring iron bars for fixing said upper structural portion are embedded in said upper structural portion, and lower end portions of said anchoring iron bars for fixing said upper structural portion are arranged so as to project in the downwards direction from the lower surface of said upper structural portion, with an upper portion of said stress transmission device being fixed to said lower end portions.
By doing this, it is possible to fix the stress transmission device to the upper structural portion very strongly.
Another aspect of the present invention is a method of constructing a structure which comprises a foundation pile and an upper structural portion which is supported by said foundation pile, comprising: digging a hole in a ground slab for embedding said pile; arranging an iron bar cage in said dug out hole; arranging a tubular shaped iron bar cage for anchoring which has been made to be of a smaller diameter than said iron bar cage, in the interior of said iron bar cage, and positioning it so that at least its upper end portion protrudes out above said dug out hole; connecting said iron bar cage for anchoring to said iron bar cage and fixing the position of said iron bar cage for anchoring within said iron bar cage; pouring concrete into said dug out hole; and thereafter fixing a lower portion of a stress transmission device to said upper end portion of said iron bar cage for anchoring, and fixing an upper portion of said stress transmission device to said upper structural portion.
According to another aspect of the present invention, said iron bar cage for anchoring is made by connecting, around an annular shaped ring member, a plurality of anchoring reinforcement members so that they extend parallel to the central axis of said ring member; by, when fixing said iron bar cage for anchoring inside said iron bar cage, providing a plurality of position maintenance members which are of the same shape to the outer circumferential surface of said ring member, so that they extend from said outer circumferential surface of said ring member in the radially outward direction of said ring member; and by arranging said iron bar cage for anchoring in this state into the inside of said iron bar cage, and fixing the other end portions of said position maintenance members remote from said ring member to said iron bar cage.